JPS6258615B2 - - Google Patents

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a new ethylene/tetrafluoroethylene copolymer (hereinafter referred to as ETFE copolymer), and more specifically, to a novel ethylene/tetrafluoroethylene copolymer (hereinafter referred to as ETFE copolymer), and more specifically, A new ETFE containing as a monomer
Regarding copolymers. Conventional ETFE copolymers are known as alternating copolymers and have excellent cut-through resistance, melt processability, chemical resistance, electrical properties, etc. However, ETFE copolymers have high crystallinity and
It has the disadvantage of becoming brittle at high temperatures. In order to improve this drawback, various modified monomers have been used.
Copolymerization into ETFE copolymers has been proposed. For example, U.S. Patent No. 3,624,250 states:
The copolymerization of ETFE copolymers with copolymerizable vinyl monomers that are free of telogen activity and provide side chains containing at least two carbon atoms has been described. However, column 3 of the US patent specification
Lines 36 to 44 state that when these vinyl monomers are copolymerized, unless the molar ratio of tetrafluoroethylene and ethylene is in the range of 60:40 to 40:60, the tensile properties or cut-through resistance will deteriorate to an undesirable degree. As described, the invention of the US patent seeks to improve the mechanical properties at high temperatures while retaining as much of the ETFE alternating copolymer properties as possible. The requirements for material properties of ETFE copolymers are very wide. For example, in the case of laminated materials with rubber, a material with excellent chemical resistance is required that is soft (i.e. has low flexural modulus and low yield strength) and can retain as much as possible the low flexural modulus of rubber. Ru. If such a laminate material is used, the sealing performance between the laminate drug stopper and the container will be improved due to the softness of the laminate film (low flexural modulus and low yield strength). There is also a strong demand for flame-retardant materials, as seen in recent plenum cable sheathing materials. For example, the limiting oxygen index in combustion tests can be compared to conventional
When comparing ETFE copolymer and polyvinylidene fluoride, there is a difference of about 30% versus 43%.
It is desired to develop an ETFE copolymer having flame retardance at least as good as polyvinylidene fluoride. Conventional ETFE copolymers cannot meet all of these property requirements. [Object of the Invention] The object of the present invention is to provide a new ETFE copolymer having softness (low flexural modulus and low yield strength) and improved flame retardancy. [Structure of the Invention] The gist of the present invention is to provide a copolymer comprising a unit based on tetrafluoroethylene, a unit based on ethylene, and a unit based on a fluorine-containing vinyl monomer that is copolymerizable with these and provides a side chain to the copolymer. A polymer in which the molar ratio of tetrafluoroethylene units and ethylene units is 62:38 to 90:10, and the content of fluorine-containing vinyl monomer units is the total number of moles of tetrafluoroethylene units and ethylene units. The new ethylene/tetrafluoroethylene-based crystalline copolymer is characterized by having a flow value of 0.1 to 5 mol %, and a flow value of 0.1 _X 10 ^-2 to 10 _X 10 ^-2 ml/sec. The present invention was made based on the discovery that a copolymer having a specific composition range of tetrafluoroethylene and ethylene satisfies the above-mentioned required properties, and is considered unfavorable in terms of physical properties in the above-mentioned US patent. Unexpectedly, useful properties were discovered in the composition range. In the copolymer of the present invention, the content of tetrafluoroethylene is 62 to 90 mol%. If the amount of tetrafluoroethylene is less than this, the copolymer becomes hard, has high bending elasticity and yield strength, and has increased flammability. On the other hand, if the content of tetrafluoroethylene is too high, melt fluidity will decrease. The preferred content of tetrafluoroethylene is 63 to 80 mol%. The modified monomer used in the present invention is not limited in type, as long as it is a fluorine-containing monomer that can be copolymerized with tetrafluoroethylene and ethylene and provides a side chain to the copolymer. Typically, the formula: CH ₂ = CXRf, CF ₂ = CFRf, CF ₂ =
CFORf, CH ₂ =C(Rf) ₂ , etc. [In the formula, X represents hydrogen or fluorine, and Rf represents a fluoroalkyl group. Monomers represented by the formula: CH ₂ =CXRf are particularly preferred from the viewpoint of copolymerizability or economic reasons. Particularly preferred are monomers in which Rf has 1 to 8 carbon atoms. Specific examples of such vinyl monomers are as follows: 1,1-dihydroperfluoropropene-1, 1,1-dihydroperfluorobutene-1, 1,1,5-trihydroperfluoropentene -1, 1,1,7-trihydroperfluoroheptene-1, 1,1,2-trihydroperfluorohexene-1, 1,1,2-trihydroperfluorooctene-1, 2,2, 3,3,4,4,5,5-octafluoropentyl vinyl ether perfluoro(methyl vinyl ether), perfluoro(propyl vinyl ether), hexafluoropropene, perfluorobutene-1, 3,3,3-trifluoro-2 -Trifluoromethylpropene-1. The content of the modifying monomer is in the range of 0.1 to 10 mol%. If the amount is less than this, no modification effect will be obtained, and if it is more than this, the thermal stability of the copolymer will decrease, and it is also economically disadvantageous. Preferably,
It is contained in a proportion of 0.5 to 5 mol%. In the case of such a composition, in the sequence distribution of monomers in the copolymer - (CF ₂ CF ₂ ) ₃ -, -
(CF ₂ CF ₂ ) ₄ --, etc. is expected to dramatically increase, resulting in the novel and useful properties described above; however, this is not to be construed as limiting the present invention. . In the present invention, the conventional polymerization method is
Methods used for polymerizing ETFE, such as bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization, and gas phase polymerization can be used. Industrially, suspension polymerization in an aqueous medium using a chlorofluoroalkane as a solvent and an organic peroxide as a polymerization initiator is preferred. As the chlorofluoroalkane, trichlorotrifluoroethane, dichlorotetrafluoroethane, dichlorodifluoromethane, chlorodifluoromethane, dichlorofluoromethane, etc. are advantageously employed.
The amount of solvent to be used is preferably 10 to 100% by weight based on water in terms of suspension dispersibility and economical efficiency. The organic peroxide used as a polymerization initiator has the formula: [In the formula, Y represents hydrogen, fluorine or chlorine, and m represents an integer of 2 to 8] Examples include peroxides represented by: Examples include perfluorohexanoyl) peroxide and di(ω-chloroperfluoropropionyl) peroxide. Also,
formula: [In the formula, l represents an integer from 1 to 10. ] Peroxides such as di(trichloroperfluorohexanoyl) peroxide are also preferred. Furthermore, hydrocarbon-based organic peroxides such as diisobutyl peroxide and diisopropyl peroxydicarbonate are also suitable. The polymerization temperature is not particularly limited, but
Industrially, the temperature may be 0 to 100°C. In order to avoid a decrease in heat resistance due to the formation of ethylene-ethylene chains in the copolymer, low temperatures are generally preferred. The polymerization pressure may generally be 0 to 50 kg/cm ² G, and a relatively low pressure of 1 to 15 kg/cm ² G is desirable for polymerization operations, and is also preferred for safety. The polymerization pressure is appropriately determined depending on the type and amount of the solvent used and other polymerization conditions such as vapor pressure and polymerization temperature. When producing the copolymer of the present invention, common chain transfer agents such as isopentane, n-hexane, cyclohexane, methanol, ethanol, carbon tetrachloride, chloroform, methylene chloride, methyl chloride, etc. may be used to control the molecular weight. Can be done. [Effects of the Invention] The novel ETFE copolymer of the present invention is softer (that is, has a lower flexural modulus and lower yield strength) than conventional ones, and has excellent flame retardancy. Since it is soft in this way, when used as a laminate material for drug stoppers as described above, the sealing performance between the laminate drug stopper and the container is improved. Furthermore, if the wire is coated,
In addition to being flame retardant, it is soft and extremely easy to handle during construction, such as wiring. [Example] Next, examples will be shown to specifically explain the present invention. The composition of the copolymer obtained in the example was calculated by dividing the difference between the total amount charged during copolymerization and the amount recovered after copolymerization by the amount of copolymer obtained. , and the composition of other monomers is determined from the content of the modified monomer and the elemental analysis values. Furthermore, the physical properties of the copolymer were measured as follows. Flow value Using a Koka type flow tester, measure the volume (ml/sec) of copolymer flowing out per unit time from a nozzle with a diameter of 2 mm and a length of 8 mm at 300℃ and under a load of 7 kg, and calculate this as the flow value. shall be. Tensile Test A copolymer molded into a JIS No. 3 dumbbell is pulled at a tensile speed of 200 mm/min at room temperature, and the yield strength, strength at break, and elongation are measured. Melting point Using a Perkin-Elmer type DSC device, 20
The melting peak when the temperature is increased at a rate of °C/min is recorded, and the temperature corresponding to the maximum value is taken as the melting point. Combustion Test Using a flammability tester model ON-1 manufactured by Suga Test Instruments Co., Ltd., the oxygen index was determined according to ASTM D2863. Flexural modulus Using STIFFNESS TESTER manufactured by Ueshima Seisakusho,
The flexural modulus at room temperature was measured. Durometer Test According to ASTM D2240, the durometer hardness (A
-type and D-type) were measured. Example 1 1.2 liters of deoxygenated water was put into a glass-lined autoclave with an internal volume of 4, and a vacuum was created. 1 kg of dichlorotetrafluoroethane was put there, and the temperature inside the tank was maintained at 15°C. 4.5 g of CH ₂ =CFC ₃ F ₆ H and 0.5 ml of cyclohexane were charged into the flask, and a mixed gas of tetrafluoroethylene/ethylene (molar ratio 97.4/2.6) was introduced under pressure to 6 kg/cm ² G while stirring. Then, di(ω-hydroperfluorohexanoyl)
Polymerization was started by charging 2.1 g of peroxide. As the pressure decreases as the polymerization progresses, tetrafluoroethylene/ethylene/CH ₂ =
CFC ₃ F ₆ H mixed gas (molar ratio 62.7:33.8:3.5) was further pressurized to maintain the polymerization pressure at 6 Kg/cm ² G. 2
0.6 g of each of the above peroxides was charged twice every hour, and polymerization was carried out for 33 hours. The contents were collected to obtain 307 g of polymer powder. Polymer composition, tetrafluoroethylene: ethylene: CH ₂ = CFC ₃ F ₆ H =
62.7:33.8:3.5 (molar ratio). Melting point: 216.5℃. Flow value 1.1×10 ^-2 ml/sec. Yield strength: 136 Kg/cm ² , breaking strength: 428 Kg/cm ² , elongation at break: 415%, flexural modulus: 8.0 _x 10 ³ Kg/cm ² . Oxygen index 43% in flammability test. A 100μ film of the polymer obtained above was laminated onto butyl rubber, and the durometer hardness was A-65. The durometer hardness of the butyl rubber was A-49 (hereinafter the same applies to Example 2 and Comparative Example 1). The durometer hardness of the copolymer sheet was D-56. Example 2 In Example 1, the initial charging amount was CH ₂ =
Repeat the same operation except using 3.5 _g of CFC ₃ F 6 H and 1.5 ml of cyclohexane and changing the additional charge composition to tetrafluoroethylene: ethylene: CH ₂ = CFC ₃ F ₆ H = 63.3: 34.0: 2.7 (molar ratio). After a polymerization time of 27.7 hours, 311 g of white powder was obtained. Polymer composition, tetrafluoroethylene: ethylene: CH ₂ =
_CFC3F6H = _63.3 :34.0:2.7 (molar ratio). melting point 225
℃. Flow value 0.45 _X 10 ^-2 ml/sec. Yield strength: 134 Kg/cm ² , breaking strength: 435 Kg/cm ² , elongation at break: 415%, flexural modulus: 6.2 _x 10 ³ Kg/cm ² . Oxygen index 45% in flammability test. A 100μ film of the polymer obtained above was laminated onto butyl rubber, and the durometer hardness was A-66. The durometer hardness of the copolymer sheet was D-56. Example 3 In Example 1, initial charging CH ₂ =
Change 4.5 g of CFC ₃ F ₆ H to 6.8 g of CH ₂ = CFC ₅ F _{10 H} , and make the additional charging composition tetrafluoroethylene:ethylene:CH ₂ = CFC ₅ F ₁₀ H = 62.9:33.8:3.3 (molar ratio). The same operation was repeated except for this, and 86 g of white powder was obtained in a polymerization time of 16.25 hours. Polymer composition, _{tetrafluoroethylene} :ethylene: _CH2 = _CFC5F10H =62.9:33.8:3.3 (molar ratio). Melting point: 220.6℃. Flow value 0.4 _X 10 ^-2 ml/sec. Yield strength: 160.9 Kg/cm ² , breaking strength: 447%, elongation at break: 380%, flexural modulus: 9.2 _x 10 ³ Kg/cm ² . Oxygen index 43% in flammability test. Example 4 In Example 1, the initially charged mixed gas composition was tetrafluoroethylene:ethylene = 98:2.
(mole ratio), repeat the same operation except that the amount of cyclohexane is 0.15 ml and the additional charging composition is tetrafluoroethylene: ethylene: CH ₂ = CFC ₃ F ₆ H = 73.2: 24.4: 2.4 (mole ratio). After a polymerization time of 11 hours, 76.7 g of white powder was obtained. Polymer composition, tetrafluoroethylene: ethylene: CH ₂ =
_CFC3F6H = _73.2 :24.4:2.4 (molar ratio). melting point
225.3℃. Flow value 3.0 _X 10 ^-2 ml/sec. Yield strength: 176 Kg/cm ² , breaking strength: 275 Kg/cm ² , elongation at break: 375%, flexural modulus: 7.0 _x 10 ³ Kg/cm ² . Oxygen index 55% in flammability test. Example 5 In Example 1, the initial charging CH ₂ =
Instead of 4.5 g of CFC ₃ F ₆ H, CH ₂ =CHC ₄ F ₉ 5.6 g, and the additional monomer composition was tetrafluoroethylene:ethylene: CH ₂ =CHC ₄ F ₉ =62.7:
The same operation was repeated except that the molar ratio was 33.8:3.6, and 78.4 g of white powder was obtained in 9.7 hours. Polymer composition, tetrafluoroethylene:ethylene: _CH2 = _{CHC4F9 =} 62.7:33.8:3.6 (molar ratio).
Melting point: 215.8℃. Flow value 0.52 _X 10 ^-2 ml/sec. Yield strength: 139 Kg/cm ² , breaking strength: 415 Kg/cm ² , elongation at break: 375%, flexural modulus: 7.0 _x 10 ³ Kg/cm ² . Oxygen index 50% in flammability test. Example 6 In Example 1, the initial charging CH ₂ =
The same operation was repeated except that CF ₂ = 90 g of CFCF ₃ was used instead of 4.5 g of CFC ₃ F ₆ H, and the additional monomer composition was changed to tetrafluoroethylene:ethylene 65:35 (mole ratio), and a white powder was obtained in 1.7 hours. 69.2
I got g. Polymer composition, tetrafluoroethylene: ethylene: CF ₂ = CFCF ₃ = 63.7: 34.2: 2.1
(molar ratio). Melting point: 241.1℃. Flow value 0.2 _X 10 ^-2 ml/
seconds. Yield strength: 93 Kg/cm ² , breaking strength: 348 Kg/cm ² , elongation at break: 427%, flexural modulus: 4.8 _x 10 ³ Kg/cm ² . Oxygen index 57% in flammability test. Comparative Example 1 Pour 1.2 liters of deoxygenated water into a glass-lined autoclave with an internal volume of 3, create a vacuum, add 1 kg of dichlorotetrafluoroethane, and lower the temperature inside the tank.
It was kept at 15℃. To this, 9.5 g of CH ₂ = CFC ₃ F ₆ H and 25 ml of n-pentane were charged, and while stirring, a mixture of tetrafluoroethylene/ethylene gas (molar ratio
83.2:16.8) was press-fitted to 6 kg/cm ² G. Then, di(ω-hydroperfluorohexanoyl)
Polymerization was started by charging 1.93 g of peroxide. Since the pressure decreases as the polymerization progresses, tetrafluoroethylene/ethylene/CH ₂ =
CFC ₃ F ₆ H mixed gas (molar ratio 52.0:45.9:2.1) was further pressurized to maintain the polymerization pressure at 6 Kg/cm ² G. 2
1.16 g of each of the above peroxides was charged twice every hour, and polymerization was carried out for 5.5 hours. The contents were collected to obtain 89.8 g of polymer powder. Composition, tetrafluoroethylene: ethylene: CH ₂ = CFC ₃ F ₆ H = 52.0:
45.9:2.1 (molar ratio). Melting point: 268.5℃. flow value
It was 0.74 _X 10 ^-2 ml/sec. Yield strength: 307 Kg/cm ² , breaking strength: 520 Kg/cm ² , elongation at break: 510%, flexural modulus: 14.0 _x 10 ³ Kg/cm ² . Oxygen index 27% in flammability test. A 100μ film of the polymer obtained above was laminated onto butyl rubber, and the durometer hardness was A-74. The durometer hardness of the copolymer sheet was D-68. Comparative Example 2 In Example 1, the molar ratio of tetrafluoroethylene:ethylene in the initially charged monomer was
94.0:6.0, and the additional monomer composition is tetrafluoroethylene:ethylene CH ₂ = CFC ₃ F ₆ H
= 56.9:40.1:3.0 (molar ratio), the same operation was repeated, and a white powder was obtained after polymerization time of 7 hours.
78.5g was obtained. Polymer composition, tetrafluoroethylene: ethylene: CH ₂ = CFC ₃ F ₆ H = 56.9:
40.1:3.0 (molar ratio). Melting point: 233.7℃. flow value
It was 0.18 _X 10 ^-2 ml/sec. Yield strength: 222 Kg/cm ² , breaking strength: 445 Kg/cm ² , elongation at break: 475%, flexural modulus: 12.3 _x 10 ³ Kg/cm ² . Oxygen index 31% in flammability test. The durometer hardness of the copolymer sheet was D-65. These results are summarized in the table below. 【table】

Claims (1)

[Scope of Claims] 1 A copolymer comprising a unit based on tetrafluoroethylene, a unit based on ethylene, and a unit based on a fluorine-containing vinyl monomer that is copolymerizable with these and provides a side chain to the copolymer. The content molar ratio of tetrafluoroethylene units and ethylene units is 62:38 to 90:10, and the content of fluorine-containing vinyl monomer units is 0.1 to the total number of moles of tetrafluoroethylene units and ethylene units. ~5 mol% and a flow value of ~0.1 _X 10 ^-2
10 _X 10 ^-2 ml/sec. 2 Content of tetrafluoroethylene units is 63~
80 mol % of the copolymer according to claim 1. 3 Content of fluorine-containing vinyl monomer units is 0.5
5 mol% of the copolymer according to claim 1 or 2. 4 The fluorine-containing vinyl monomer unit has the formula: [In the formula, X represents hydrogen or fluorine, and Rf represents a fluoroalkyl group. ] The copolymer according to any one of claims 1 to 3.